Clam or oyster dredge.



No. 705,975. Patented July 29, |992. w. A. THoMPsoN.

CLAM 0R OYSTER DREDGE.

(Applicazion med oct. 2s, 1901.)

2 Sheets-Sheet I.

N0. 705,975. Patented luly 29, |902.

W. A. THOMPSON.

CLAM 0R DYSTER DBEDGE.

(ppliation led Oct. 28, 1901.) (No Model.) 2 Sheets-Sheet 2.

TN: cams PETERS cn. vnorammo.. wAsHmcTou. u. c.

UNITED STATES 4PATENT OFFICE.

VILLIAM A. THOMPSON, OF LA GROSSE, VISCONSIN.

CLAM OR OYgSTER DREDKGE.

SPECIFICATION forming part of Letters Patent No. 705,975, dated July 29, 190.2. Application led October 28, 1901. Serial No. 80,301. (No model.)

T0 @ZZ whom, t may concern:

Be it known that LWILLIAM A; THOMPSON,

a citizen of the United States, residing at La Crosse, in the county of La Crosse and State of Wisconsin, have invented a new and useful Clam or Oyster Dredge,- of which thefollowing is a specification.v I

My inventionis an improvedclam and oyster dredge adapted to raise clams and oysters from the beds of rivers, bays, and streams by suction and to separate the clamsand oysters from the sand and mud raised therewith; and it consists in the peculiar construction vand combination of devices hereinafter fully set forth and claimed.

In the accompanying drawings, Figure lis top plan view of va clam and 'oyster dredge constructed in accordance with my invention. Fig.2 is an end elevation of the same. Fig. 3 is partly a transverse sectional View of the same, taken on a plane indicated by the line a a of Fig. l. Fig. 4 is a detail longitudinal sectional View taken through the dischargepipe and showing the separating screen therein. Fig. 5 is a detail transverse sectional view taken on a plane indicated by the line b b of Fig. 4. -Y

In the embodiment of my invention here shown a centrifugal suction or other suitable form of pump l' is mounted for operation on a iioat or barge 2, 3 being the suction-pipe, which in practice extends to the bed of the stream, bay, or other body of Water on which the dredge is used, and 4 being the dischargepipe, Which leads from the saidpump. For the purpose of illustration I have here shown the centrifugal'pump provided with a powerpulley 5, by which it may be driven. The discharge-pipe 4 is provided at a suitable distance from its outer end with a member 6, coupled therein, which member dis provided With a vertical discharge branch 7'.` A separating-screen 8 is located and secured in the discharge-pipe at a suitable distance beyond the discharge branch 7. As here shown, the said separating-screencomprises a series of bars spaced apart a suitable distance to prevent tlie shells of clams or oysters from passing between them. Within the scopefof my invention, hoWever,-said screen may be of any suitable construction, and I do not desire to limit myself in this particular. A suitable frame 9 is shown on the barge or., float, over which frame the discharge-pipe 4 extends, and in the said frame is an endless movable `separating-screen 10. -The same is here 'shown as composed of a pair of endless chains ll, connected together by transversely-disposed bars l2, Which are appropriately spaced apart to LAprevent clam or oyster shells frompassing between them, and suitable revoluble ele- 'same into a barge or other suitableireceptalcle or vessel. l vtransversely under the endless traveling car- A mud-chute 16 is disposed rier-screen 10 and is adapted to discharge material overboard.

YIn the operation of my invention the clams and Voysters raised from the bed," together with a quantity of sand, mud, or silt, and a volume of water by the pump and discharged therefrom through the pipe 4, are separated `from the foreign matter by the screen 8 and discharges through the branch discharge 7 onto the-endless traveling carrier-screen 10. A portion of the foreign matter is discharged directly overboard from the pipe 4, and such of the foreign matter as is discharged upon the endless traveling carrier-screen is Washed an d separated from the clams or oysters and falls through the said carrier-screen onto the mud-chute 16, which discharges the same overboard, while the clams or oysters which have been separated from the foreign matter by the action of the stream of water from the pump and the screens 8 l0 are discharged from the latter onto the chute l5, as rwill be readily understood.

My invention is particularly adapted for dredging the clam-beds of the .Mississippi river and other streams from the shells of which the so called pearl buttons are made. Heretofore these clams have been sys IOO

raised by fishermen by hooks and lines, and such dredges as have been tried for doing the Work have been discarded, because it Was found more costly to pick out the shells from the mud and sand with which they were commingled than to obtain the shells in the Inanner above stated. My improved dredge sepa- 3. A dredge having a discharge-conduit provided with a discharge branch and a screen beyond the latter, in combination with an endless traveling carrier-screen onto which said branch discharges, substantially as described.

4. AA dredge having a discharge-conduit provided with a discharge branch and a screen beyond the latter, in combination with a carrier-screen onto which said branch discharges, a chute under said carrier-screen to discharge the material that passes through the latter and a chute on Which'the material carried by said carrier is discharged by the latter, substantially as described.`

In testimony that I claim the foregoing as my own I have hereto affixed my signature in the presence of tWo witnesses.

WILLIAM A. THOMPSON.

Witnesses:

J. F. ,MCDoNoUGiL GERTRUDE HUBBARD. 

